Plate freezers are well known in the food processing industry, particularly in the production of pet foods such as red meat pet food offal, fish for pet food, fruit and vegetable pulp, water (block ice) and waste organic product that requires freezing prior to disposal.
Plate freezers generally comprise a plurality of refrigerated plates mounted within a frame to define a space therebetween, into which the material is delivered to be frozen. Refrigerant is delivered to the plates to provide form such that the plates act as evaporators to absorb heat energy from the product thereby rapidly freezing the product. Once frozen the refrigerant circuit is able to be reversed to provide warm gas to the plates to defrost the contact zone between the frozen product and the plate surface to facilitate removal of the frozen product from the plates. In most commercially available plate freezing devices, it is desirable that the material to be frozen is able to be quickly loaded into the space formed between the plates and that the frozen material can then be quickly removed as required.
For this reason, a variety of different types of plate freezers have been proposed to improve the automation of such devices so as to reduce the amount of labour required to operate the devices and to minimise handling of product both pre- and post-freezing. Such systems have included hoppers for filling the plate freezers as well as various means for automatically releasing the frozen blocks onto a conveyor system, all with various degrees of success.
Typically, most commercially available bare block plate freezers employ a vertical lift system that, after the product has been frozen and the interface between the product and plates defrosted, the plates are separated and the floor of the system is raised to lift the frozen blocks above the top of the plates for removal. The floor of each of the plates is typically attached to a common rail which is activated by a vertical ram to raise the blocks above the top edge of the plates for removal. Removal is typically achieved by manually transferring the frozen blocks onto a pallet or conveyor that extends parallel to the plate freezer and in some instances a movable slide can be assist to aid in the manual transfer of the blocks. The conveyor is then able to transfer the frozen block to a palletising station where it is then able to be guillotined, palletised and wrapped, as desired.
A problem with such existing commercial plate freezers is that they are labour intensive as it can take up to 10 minutes to unload each plate freezer depending upon the number of plates employed. Further, as the blocks are frozen to −15° C. and can weigh up to 70 Kgs, the manually handling of these blocks can present significant safety hazards and requires much skill and effort. Further, through handling the blocks there may be a risk of bacterial contamination of the product. Also, most existing commercial applications employ a conveyor that extends parallel to the plate freezer unit which is an inefficient use of space.
Thus, there is a need to provide a plate freezer apparatus that is an improvement over existing devices and which addresses at least some of the disadvantages of existing systems.
The above references to and descriptions of prior proposals or products are not intended to be, and are not to be construed as, statements or admissions of common general knowledge in the art. In particular, the above prior art discussion does not relate to what is commonly or well known by the person skilled in the art, but assists in the understanding of the inventive step of the present invention of which the identification of pertinent prior art proposals is but one part.